The surfaces of wood, fiberglass and other construction materials often require sanding to function well for constructing objects, structures, and supports. This is most significant for surfaces that need to be painted or sealed or that will be in regular physical contact (with skin, clothing, etc.). Creating a smooth surface is a simpler task when sanding is performed on flat surfaces, such as wooden boards or walls. However, there are many uses of the above materials that involve curved or angled surfaces that are more difficult to sand. With these forms of materials, flat sandpaper or sand blocks may be difficult to employ. The problem is compounded when the sanding work requires pressure from individual fingers or groups of fingers to keep in efficient contact with the surface. This type of usage of sandpaper can stress or abrade a user's fingers and can cause a user's skin to come in contact with rough surfaces or splinters. Fiberglass shards or splinters present a unique concern in this regard.
As a further problem, surfaces, whether curved or flat, may be difficult to reach or otherwise inaccessible by standard sandpaper or sand blocks. For example, in boat construction, all wood surfaces, inside or out, must be fully sanded and sealed to inhibit salt damage and rot. However, given the tight geometries of boat segments or areas, sanding usually requires lengthy, difficult and painful detail work with finger pressure, sometimes without clear view.